The professional's version of Facebook for use as a career networking tool. You have a "public profile" that corresponds to a Facebook "wall." Instead of "friends", you have "connections." You gain access to the connections of your connections unless they "hide" them and you can hide yours. When you have a connection, you have their contact information. You can have professional recommendations posted on your page.

LinkedIn is also a frequently used sock puppet for identity thieves. Never accept connections from people you don't know. Never put your real physical address into the contact section; give an e-mail address and an unlisted telephone number.

LinkedIn is also a tool that many recruiters (scalpers/headhunters) use in a dishonest manner. Their attempts to connect with you are phishing expeditions to get your connection list. The job that they claim to have is nearly always fake; it is bait, if you accept their connection you will never hear from them again or they will tell you that the job is filled. Recruiters always hide all their connections so you get nothing from them (all take and no give)

Ignore any offer for connections from a recruiter. If you want to contact them, do so outside of LinkedIn. Read their public profile (many recruiters have contact information there). If so, call or Email directly (use unlisted phone). If not, send an InMessage through LinkedIn giving them only an Email address and an unlisted phone number.

LinkedIn can be a useful tool to keep up with your professional contacts

1. A place where unemployed 40 somethings go because their kids told them about social media and their neighbor (Never even visited LinkedIn twice) recommended they check it out during small-talk. Then the unemployed 40 year old spends one afternoon making 500 connections and harassing people who haven't been back to LinkedIn in a year; with their resume.

2. A profile graveyard for entry level corporate kids who do not want to share their Facebook profile with their superiors.

3. A place where salesmen and MLM marketers pump their wares until they realize no-one ever returns or uses LinkedIn.

Bob: "Hi Jane how are you doing?"

Jane: "I'm ok, still looking for a job."

Bob: "You should go on LinkedIn, it's like a Facebook for professionals."